Actes du premier colloque sur les composites actifs supraconducteurs / Proceedings of the first conference on the active superconducting composites
J. Phys. IV France 08 (1998) Pr1-51-Pr1-55
Electrical properties and corrosion of Bi-2223 coatings on silver wires directly synthetized from a Bi-2223 precursor or from a Bi-2223/Bi-2212 mixtureC. Lamine1, 2, F. Ben Azouz2, T. Badeche1, O. Monnereau3, M. Ben Salem1, 2 and C. Boulesteix1
1 MATOP, URA 1530, Case 151, Faculté des Sciences de Saint Jérôme, 13397 Marseille cedex 20, France
2 Laboratoire de Physique des Matériaux, Faculté des Sciences de Bizerte, Tunisie
3 LPCM, Université de Provence, 3 place Victor Hugo, 13331 Marseille cedex 3, France
Superconducting wires are prepared by coating of a silver substrate, by sintering of a slurry deposited onto the metal core and containing a grinded (Pb doped) Bi-2223 ceramic, a grinded Bi-2223/Bi-2212 mixed ceramic or a grinded mixture of the Bi-2223 precursors, and of 20% PbO in excess. The resistance-versus-temperature R(T) curves obtained for a 6 days sintering at 835°C presented only one drop, with Tc0 = 108K (107K when the slurry is a mixture of the Bi-2223 precursors). When the coating is obtained from a grinded Bi-2223/Bi-2212 mixed ceramic the R(T) curves are better (higher Tc and narrower ΔTc) than the R(T) curves obtained with the ceramic used for preparing the wires, for which Tc0 = 34K. The role of PbO in excess is discussed. These coatings hold rather well against corrosion by waper vapor at 90°C and the Bi-2223 phase is less corroded than the Bi-2212 phase.
© EDP Sciences 1998